The Nobel Assembly at Karolinska Institutet awarded the 2015 Nobel Prize in Physology & Medicine earlier this month. The honors went to the scientists who discovered artemisinin and avermectin, which respectively treat malaria and parasitic infections. We’ll explore ivermectin in another post, but today let’s talk artemisinin!

Chemistry of artemisinin

Artemisinin is a sesquiterpene lactone compound that contains an endoperoxide bridge – a functionality biochemists are unaccustomed to seeing, but is believed to be essential for the drug’s anti-malarial activity. The drug is the fastest treatment available for malaria cause by the parasite Plasmodium falciparum.


The structure of artemisinin. Note the lactone in the lower portion of the molecule above, and the peroxide bridge -O-O- in the top left portion.

Artemisinin is biosynthesized by the plant Artemisia annua,  or sweet wormwood. The plant is native to China and Vietnam, but is also grown in East Africa. When the plants reach full size after about 8 months of growth, the leaves are dried and then artemisinin is extracted by organic solvents, with hexane usually being the solvent of choice.

Artemisia annua, plant

Leaves of Artemisia annua.

Semi-synthetic pathways to artemisia also exist. Genetically engineered yeasts can produce artemisinic acid, a precursor to artemisinin. Artemisinic acid can then be purified and further modified synthetically to yield artemisinin. Scientists have also engineered tobacco plants to produce artemisinic acid.


How artemisinin works is hotly debated. The likeliest mechanism involves radical formation by the endoperoxide bridge. In this mechanism, iron from the heme in blood reduces the peroxide bond in artemisinin, producing an iron-oxo species. This iron-oxo species leads to to a series of reactions that generate radical oxygen species that kill the parasites causing malaria. Experiments show that exposure to artemisinin leads to damage in parasites’ vacuolar membranes, and that the compound is present in the Golgi, endoplasmic reticulum, and mitochondria of P. falciparum after exposure.


In 1967, Tu Youyou led a Chinese research program to find a treatment for malaria as mandated by Chairman Mao.  After scouring the historic literature, for homeopathic and folk remedies to malaria symptoms, Tu Youyou stumbled across a recipe for extracting Artemisia annua in The Handbook of Prescriptions for Emergency Treatments written in 340 BC . After modernizing and improving the extraction prtocol,  Tu Youyou discovered the extract was indeed anti-malarial. And upon purification artemisinin, which is named qinghaosu in Chinese, was the compound responsible for its activity.  The results of his research were published in the Chinese Medical Journal in 1979.

So, that’s artemisinin in a nutshell. Artemisinin has saved countless lives world-wide. It is typically used in combination therapies these days. But even so, malaria still is estimated to kill over 1 million people each year.

preserving mars

Dark streaks indicate the flow of water down Martian slopes. Photo from

About a week ago, NASA presented compelling evidence of flowing water on The Red Planet. The water flows foster hope that there may yet be life to discover on Mars. Scientific American discusses the  hardest part of discovering the first Martians: preventing contamination from Earth.

The problem is not exploding rockets, shrinking budgets, political gamesmanship or fickle public support—all the usual explanations spaceflight advocates offer for the generations-spanning lapse in human voyages anywhere beyond low Earth orbit. Rather, the problem is life itself—specifically, the tenacity of Earthly microbes, and the potential fragility of Martian ones. The easiest way to find life on Mars, it turns out, may be to import bacteria from Cape Canaveral—contamination that could sabotage the search for native Martians.

Certain areas of Mars are designated as “Special Regions” by the Committee on Space Research, or COSPAR, and restricted from earthly visitors. These special regions appear to have the right topography and geothermal profiles to support life. By prohibiting visitors, astronomers hope to preserve any potential extraterrestrial life. But are these designations enough to protect Martian soil and species from Earth’s most relentless invaders?

Read more at Scientific American.

do it for the snap

Dangerous selfies. Kirill Oreshkin takes selfies from the top of some of the world’s tallest buildings. Image from  The Huffington Post.

Are you a selfie afficionado? Would you do anything for the vine? More and more of us are being caught up in selfie-mania and hurting ourselves trying to get the perfect picture. Mashable reports that more people have been killed while taking selfies this year than from shark attacks… not that that is all that meaningful of a statistic. So far this year 12 people have died trying to take selfies, compared to 8 deaths from shark attacks. Many more have likely been injured. Some places have begun to ban selfie sticks to prevent sight-seers from tempting fate. So if you’d do anything for a snap, make sure you’re being safe as well.

buckyballs from outer space



Buckminsterfullerene, also known as C60 and buckyballs, are believed to cause interstellar absorption patterns that have confounded scientists for decades.

For at least 100 years scientists have been observing unknown absorption bands in outer space. These diffuse interstellar bands were of unknown origin, until just recently.

Astronomers have believed buckyballs, or fullerene to be behind the phenomena since the mid-90s. Fullerenes are molecular carbon, made of 60 carbon atoms and shaped like soccer balls or geodesic domes. The wavelengths of light that buckyballs absorbed when encased in an unreactive frozen solids were similar to the patterns observed in space. But, since they were unable to observe the molecules under space-like conditions, it was not possible to claim that they were the definite cause. Over the next 20 years, researchers have worked on observing C60 in space-like conditions. Now, John Maier has observed behavior of fullerene ions at close to absolute zero and under high vacuum.  They found spectral lines at wavelengths of 9577 and 9632 angstroms, which match the patterns seen in space. This result offers considerable evidence that the molecules are behind the bands. The research is published at Nature.


the chemistry of wine

Have you ever wondered what makes wine so good? Scientifically speaking, of course.  The team at Reactions explains the science behind the flavor profiles of different vintages.

antibiotic advances

Staph aureus

Drug resistant Staph aureus

Over on, Sara Reardon provides a brief rundown on different alternatives to traditional antibiotic treatments. These alternatives are among some of the most promising solutions to growing antibiotic resistance. Sara mentions peptides, phages, metals and gene editing techniques. Phages have been used clinically for many years especially in Eastern Europe. And metals like silver and copper have been used as antibiotics since at least the 4th century B.C. Silver in particular causes bacteria to act like zombies and kill other live bacteria after they’ve been treated.

Antibiotic peptides are commonly isolated from the skin of frogs, and also in fungi. These peptides are typically 10–50 amino acid residues long and have many cationic residues. They can act in multiple ways, but most permeabilize and disrupt cellular membranes causing bacterial contents to leak out of the cell.

Gene editing is gaining popularity as scientists makes continued improvements to CRISPR technologies.  Bacteria usually use CRISPR to develop resistance to phages and viruses, but scientists are engineering ways to use this to make bacteria attack themselves. As the technology develops, some scientists believe antibiotic CRISPR systems have the potential to be much better than traditional antibiotic treatments.

Taken as a whole, development on all these fronts signals that research on new antibiotics will continue to progress, even as traditional small molecule antibiotics are becoming harder to find.